Remove Client.NewQuery()

[chrismarget-j]

Client.NewQuery() was written when Chris understood graph queries less well than he does now. In particular, before he understood that there are different types of query structures:

• path queries (those which start with node()
• match queries (those which start with match()
• possibly others?

Client.NewQuery() returns a PathQuery primed with a client and a blueprint ID.

All uses of NewQuery() in the terraform provider have been replaced with one of these:

• new(PathQuery).SetBlueprintId().SetClient()
• new(MatchQuery).SetBlueprintId().SetClient()

This PR:

• Removes Client.NewQuery() and Client.newQuery()
• Converts uses of those methods to use the type-specific query instantiations cited above.

Closes #21